/* 导航 */
.nav>ul li:nth-child(2)::after {
  /* 导航li经过时，填充下面的颜色条 */
  content: '';
  display: block;
  width: 120px;
  height: 4px;
  background-color: #47a9e2;
  position: absolute;
  bottom: 0;
}

.nav>ul>li:nth-child(2) a {
  color: #296c93;
}

/* 主体 */
.main {
  background-color: #f2f2f2;
  padding-bottom: 245px;

}

.main img {
  width: 100%;
}